In an effort to increase the efficiency of spectrum use for wireless communications, spectrum regulatory authorities are proposing ways to share spectrum otherwise licensed to a particular service provider.
One proposal introduced by the U.S. Federal Communications Commission (FCC) is to permit otherwise unlicensed devices to transmit in a frequency band that has been licensed to a service provider by the regulatory authority for exclusive use. According to a proposed secondary usage policy, these so-called unlicensed devices may transmit in a licensed frequency band as long as the radio energy they emit stays below an interference threshold thereby not degrading the licensed spectrum service's providers operations.
Alternatively, the FCC may permit secondary devices to transmit in a licensed spectrum as long as these devices first measure the spectrum and determine that no licensed devices are active in the area during a time interval when it is desired to make a transmission from an unlicensed device. This is referred to as a “Cognitive Radio” approach.
In the event these proposals are adopted, a need may arise to enforce compliance with the interference threshold and other conditions that are established to permit sharing of licensed spectrum.